In the modern society, there exist a number of payment scenarios, including Internet-based payment, completion of transactions in cash, and completion of transactions using bank cards. Internet-based payment has been adopted by more and more users and merchants thanks to its simple implementation, quick operation, and high security and reliability.
In contrast, payment in cash or by a bank card requires the users to carry cash or a bank card. In a scenario where payment needs to be made in cash, such as taking a metro train, a self-service ticketing bus, or a taxi, an exact amount including small changes may be necessary. This requirement may cause inconveniences to the user. In another scenario using a bank card for payment, the payee (e.g., merchant) may need to install a point of sale (POS) machine which may increase additional transaction cost. In addition, payment by bank card may yet to be implemented in some scenarios such as taking subway, a self-service ticketing bus, or a taxi.